typically the easy way to tell the differance between the 700 and the 750 is the color of the engine...if its aluminum it is typically a 750, if it is black, it typically is a 700... I say typically because people have been known to paint the engines different colors.
Your bike isn't stock though... the ears have been shaved, and its been coastered (I think... can't quite tell because of the lighting, can you get pics of the other side as well, I might be able to see a little clearer.) You also have the Kawasaki Fire and steel Extended backrest, and sadleman seat cover.
You have a sweet ride, and welcome to the madness... you found the best source of information on the VN700/7500 on the planet.